{{define "content"}}
    <h1 class="hello">This is content!!!!</h1>
    <p>This page not define：
    <pre> {{`{{define "head"}}{{end}}`}}</pre>
    <pre> {{`{{define "foot"}}{{end}}`}}</pre>
    So, it's output default content!</p>
    <hr>
    <p><a href="/block">block page!</a></p>
{{end}}